Stock Rocker Ratios

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Teedog

Teedog

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Hey all,

I am led to believe that the Stock steel stamped rockers were generally not quite up to their Factory rocker ratio rating of 1.5:1 however are the ductile iron adjustable rockers as those found on the solid cammed 273 small blocks any more accurate.

I'm just not keen on throwing in a new cam knowing that I'm not really getting the intended valve lift. Has anyone attempted to accurately measure the ratio on the 273 rockers?
I'm guessing that they also could vary substantially?

Roller Rockers for Mopars are expensive? Any other new Rocker alternatives I should know about?

Cheers,
Teedog.
 
Yes the ductile iron rockers were typically right on the money. Though some will argue, they have probably never measured them, or not measured them correctly. All of the ones I have ever measured were right on the mark. It's a pretty commonly known fact that the stamped steel ones sucked.
 
Agreed. The mechanical 273 rockers can and have been found to be off. You can have them re-worked and corrected when they get checked for there accuracy. Hughes engines can do this for you.

It has also been found that some after market companies have rockers not living up to the advertised ratio as well.
Do be aware that even if the ratio is dead balls on accurate, you will loose lift due to the pushrod angles. (AKA - geometry)

Roller rockers are pricey for most any manufacturer except a Chevy, so, in a major of speaking, a lot depends on you wallet thickness and need or want. Try a search @ summitracing.com and price check them. (And in another plug for) Hughesengines.com also has really nice rockers in 1.5-&-1.6 for the LA heads.

HP wise, there only a few HP. But performance wise, as in set up, accurate ratios, getting that intended lift, properly actuation the valves, there a good purchase IMO. Are they needed? No. But they do help insure that your getting the cam action from the cam that you purchased based on spec's. So getting every last bit of what you purchased, from the cam, a good accurate ratio and set up of the rocker arm is needed.
 
I think Mike from MRL has measured a few sets of the stamped steel rockers before...ranged from 1.4 to 1.6
 
the stamped rockers are all over the place, the old iron 273 rockers are better, but they vary also. They can be corrected though, I have a few sets done by rocker arm specialties out of California, a set of blueprinted 1.5s and a set of 1.6s All they really do is move the adjuster location, and rebush them. Nice pieces but pricy for what they are.
 
I f you are not trying to squeeze the last 10nth of a second out of the engine it will not make a big difference . I use the old 273 style rockers , did not see any change when I switched to them .
 
OK thanks for that guys. Will assess my options. There are a set of 273 rockers for sale here locally but without shafts or spacers. Not too expensive so I might take a look at those perhaps.

Thanks again,
Teedog
 
jerry6 said:
I f you are not trying to squeeze the last 10nth of a second out of the engine it will not make a big difference . I use the old 273 style rockers , did not see any change when I switched to them .
Click to expand...

This ^^^^^ is the best answer of all.
 
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